(PHP 4 >= 4.0.6, PHP 5)is_callable -- Verify that the contents of a variable can be called as a function
Verify that the contents of a variable can be called as a function. This can check that a simple variable contains the name of a valid function, or that an array contains a properly encoded object and function name.
var parameter can be either the name of a function stored in
a string variable, or an object and the name of a method within the
object, like this:
syntax_only argument is TRUE the
function only verifies that
var might be a
function or method. It will only reject simple variables that are
not strings, or an array that does not have a valid structure to be
used as a callback. The valid ones are supposed to have only 2
entries, the first of which is an object or a string, and the
second a string.
callable_name argument receives the
"callable name". In the example below it's
"someClass:someMethod". Note, however, that despite the
implication that someClass::SomeMethod() is a callable static
method, this is not the case.